//  CEC2009_UF3.java
//
//  Author:
//       Antonio J. Nebro <antonio@lcc.uma.es>
//       Juan J. Durillo <durillo@lcc.uma.es>
//
//  Copyright (c) 2011 Antonio J. Nebro, Juan J. Durillo
//
//  This program is free software: you can redistribute it and/or modify
//  it under the terms of the GNU Lesser General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU Lesser General Public License for more details.
// 
//  You should have received a copy of the GNU Lesser General Public License
//  along with this program.  If not, see <http://www.gnu.org/licenses/>.

package org.uma.jmetal.problem.multiobjective.cec2009Competition;

import org.uma.jmetal.problem.impl.AbstractDoubleProblem;
import org.uma.jmetal.solution.DoubleSolution;

import java.util.ArrayList;
import java.util.List;

/**
 * Class representing problem CEC2009_UF3
 */
@SuppressWarnings("serial")
public class UF3 extends AbstractDoubleProblem {
    
 /** 
  * Constructor.
  * Creates a default instance of problem CEC2009_UF3 (30 decision variables)
  */
  public UF3() {
    this(30);
  }
  
 /**
  * Creates a new instance of problem CEC2009_UF3.
  * @param numberOfVariables Number of variables.
  */
  public UF3(int numberOfVariables) {
    setNumberOfVariables(numberOfVariables) ;
    setNumberOfObjectives(2) ;
    setNumberOfConstraints(0) ;
    setName("UF3") ;

    List<Double> lowerLimit = new ArrayList<>(getNumberOfVariables()) ;
    List<Double> upperLimit = new ArrayList<>(getNumberOfVariables()) ;

    for (int i = 0; i < getNumberOfVariables(); i++) {
      lowerLimit.add(0.0);
      upperLimit.add(1.0);
    }

    setLowerLimit(lowerLimit);
    setUpperLimit(upperLimit);
  }

  /** Evaluate() method */
  @Override
  public void evaluate(DoubleSolution solution) {
    double[] x = new double[getNumberOfVariables()];
    for (int i = 0; i < solution.getNumberOfVariables(); i++) {
      x[i] = solution.getVariableValue(i) ;
    }


  	int count1, count2;
		double sum1, sum2, prod1, prod2, yj, pj;
		sum1   = sum2   = 0.0;
		count1 = count2 = 0;
 		prod1  = prod2  = 1.0;

    
    for (int j = 2 ; j <= getNumberOfVariables(); j++) {
			yj = x[j-1]-Math.pow(x[0],0.5*(1.0+3.0*(j-2.0)/(getNumberOfVariables()-2.0)));
			pj = Math.cos(20.0*yj*Math.PI/Math.sqrt(j));
			if (j % 2 == 0) {
				sum2  += yj*yj;
				prod2 *= pj;
				count2++;
			} else {
				sum1  += yj*yj;
				prod1 *= pj;
				count1++;
			}
    }
    
    solution.setObjective(0,  x[0] + 2.0*(4.0*sum1 - 2.0*prod1 + 2.0) / (double)count1);
    solution.setObjective(1, 1.0 - Math.sqrt(x[0]) + 2.0*(4.0*sum2 - 2.0*prod2 + 2.0) / (double)count2);
  }
}
